某深基坑支护结构内力与变形研究

Study on inner force and deformation of supporting structure for deep foundation pit

以某深基坑支护结构位移与内力监测为依据,并结合计算分析探讨了位移与内力大小的变化规律。实测表明施加的锚杆预应力有10%～25%的损失,在开挖过程中锚杆轴力增加约10%左右。钢支撑的轴力随开挖深度增加而增加,轴力大小、变化与开挖方式、速度及下层支撑的逐一拆除有关;支护桩的变形随桩深、支撑条件变化而变化。基坑顶部的水平位移以坑壁中央最大,靠端部位移较小。总的来说,理论分析与实测结果大体一致,但由于支护结构受力与变形的复杂性及施工的影响,使得理论计算值与实测值存在一定的差异。

The observing and theoretically analyzing inner force and displacement of the supporting structure for foundation pit are carried out. There are different losses of prestress of anchors mostly about 10%-25%, and increase of inner axial force of anchors about 10% during the construction. The inner axial force of steel props increases with the increment of the excavation depth; and its value changes with the varieties of excavation mode, velocity and dismantlement of the underlying props in order. The horizontal displacement of the retaining pile body is related to the pile depth and supporting condition. The deformation of the earth surface is the largest in the middle and the smaller at the end. The calculating data are generally accordant with the measuring data; but there are some differences between them because of the influences of various factors and the dynamic construction.